On Tue, 2003-10-21 at 18:43, Martin Johansson wrote:
> On Mon, Oct 20, 2003 at 11:07:40PM +1000, Ken Foskey wrote:
>
> >
> > If anyone is on a very fresh version of K2.6 with extra patches can you
> > please run this code and see if it crashes. It fails on all K2.6 up to
> > Test6 release. I would be interested to hear of any success.
>
> I don't think it's related to the kernel version.
>
> > There should be no segfault and another signal caught.
> >
> > If there is any obvious blunder with this code let me know. Looks
> > pretty right to me though I don't use signals much at all.
>
> The problem is that you never return from the signal handler. Now you're
> getting a SIGSEGV during execution of the SIGSEGV handler and the signal is
> probably forced to SIG_DFL, otherwise you could get an infinite signal
> loop. Return from the handler instead of a longjmp and you should be ok.
The following code behaves the same under K 2.4 and K 2.6 so there is
something different for SEGV to SIGINT. Can anyone explain?
If you run this:
./a.out and hit ^C twice with a delay you get:
$ ./a.out
Hello World
Hello World
OUCH - I got signal 2
Hello World
$
***but***
$ ./a.out x
Hello World
OUCH segv - I got signal 11
Segmentation fault
$
So returning from a segv signal will fail the program.
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
void ouch_segv( int sig )
{
printf( "OUCH segv - I got signal %d\n", sig );
(void) signal( SIGSEGV, SIG_DFL );
}
void ouch( int sig )
{
printf( "OUCH - I got signal %d\n", sig );
(void) signal( SIGINT, SIG_DFL );
}
int main( int argc, char ** argv )
{
char a;
(void) signal( SIGINT, ouch );
(void) signal( SIGSEGV, ouch_segv );
while( 1 ) {
printf( "Hello World\n" );
fflush( stdout );
if( argc > 1 ) {
a = *((char*)0);
}
sleep( 1 );
}
}
--
Thanks
KenF
OpenOffice.org developer
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